CN114026148A

CN114026148A - Method for producing polyether ester carbonate polyols

Info

Publication number: CN114026148A
Application number: CN202080049115.3A
Authority: CN
Inventors: T·E·穆勒; C·居特勒; M·A·苏巴尼; W·莱特纳
Original assignee: Covestro Intellectual Property GmbH and Co KG
Current assignee: Covestro Intellectual Property GmbH and Co KG
Priority date: 2019-07-05
Filing date: 2020-06-26
Publication date: 2022-02-08
Also published as: EP3760663A1; EP3994198A1; WO2021004814A1; US20220235176A1

Abstract

The subject of the invention is a process for preparing polyether ester carbonate polyols by the catalytic addition of alkylene oxides and carbon dioxide onto H-functional starter substances in the presence of double metal cyanide catalysts, which comprises the following steps: (. alpha.) A partial amount of H-functional starter substance and/or of suspension medium which is free of H-functional groups is initially loaded into the reactor, optionally together with DMC catalyst, (y) alkylene oxide and optionally carbon dioxide are metered into the reactor during the reaction, characterized in that lactide is metered into the reactor in step (. gamma.).

Description

Method for producing polyether ester carbonate polyols

The invention relates to a method for producing polyether ester carbonate polyols by adding alkylene oxides, lactides and carbon dioxide to H-functional starter substances in the presence of double metal cyanide catalysts. The invention further relates to polyether ester carbonate polyols obtainable by this process.

The preparation of polyether carbonate polyols by catalytic reaction of alkylene oxides (epoxides) and Carbon Dioxide in the presence of H-functional starter substances (starters) has been the subject of considerable research for more than 40 years (e.g.Inoue et al, polymerization of Carbon Dioxide and Epoxide with organic Compounds; Die Makromolekulare Chemie 130, 210-220, 1969). This reaction is schematically shown in scheme (I), wherein R is an organic group, such as alkyl, alkylaryl or aryl, each of which may also contain heteroatoms, such as O, S, Si and the like, and wherein e, f and g are integers, and wherein the products shown here in scheme (I) with respect to the polyethercarbonate polyols are to be understood as meaning only that blocks having the structure shown can in principle be present in the resulting polyethercarbonate polyol, but the order, number and length of the blocks and the OH functionality of the starter can vary and are not limited to the polyethercarbonate polyols shown in scheme (I). This reaction (see scheme (I)) is very advantageous from an ecological point of view, since it represents the conversion of greenhouse gases such as CO₂And converted into a polymer. The further product formed, which is in fact a by-product, is a cyclic carbonate as shown in scheme (I) (e.g. at R = CH)₃Propylene carbonate).

WO 2013/087582 a2 discloses the trimerization of propylene oxide, anhydride and carbon dioxide in the presence of double metal cyanide catalysts, wherein one or more H-functional starter substances are first loaded into the reactor. Neither lactide nor the viscosity of the resulting polyether ester carbonate polyol is disclosed.

The subject matter of EP 2604642A 1 is a process for preparing polyether carbonate polyols by the catalytic addition of carbon dioxide and alkylene oxides onto one or more H-functional starter substances in the presence of a Double Metal Cyanide (DMC) catalyst, wherein in a first activation stage the DMC catalyst and at least one H-functional starter substance are initially charged and in a second activation stage the DMC catalyst is reacted by addition of at least one alkylene oxide, CO₂And at least one cyclic anhydride, and in a third step [ polymerization stage ]]Adding at least one alkylene oxide and CO₂. Neither lactide nor the viscosity of the resulting polyether ester carbonate polyol is disclosed.

WO 2014/033070 a1 discloses a process for preparing polyether carbonate polyols by addition of alkylene oxides and carbon dioxide onto one or more H-functional starter substances in the presence of double metal cyanide catalysts, wherein a suspension medium of one or more compounds which are free of H-functional groups and are selected from aliphatic lactones, aromatic lactones, lactides, cyclic carbonates having at least three optionally substituted methylene groups between the oxygen atoms of the carbonate groups, aliphatic cyclic anhydrides and aromatic cyclic anhydrides is first loaded into a reactor and one or more H-functional starter substances are metered continuously into the reactor during the reaction. Neither the effect of lactide on the viscosity of the polyether carbonate polyol nor the metered addition of lactide during the copolymerization process is disclosed.

It is an object of the present invention to provide a process for preparing polyether ester carbonate polyols, wherein the polyether ester carbonate polyols obtained have a low viscosity.

The object is achieved by a process for preparing polyether ester carbonate polyols by the catalytic addition of alkylene oxides and carbon dioxide onto H-functional starter substances in the presence of double metal cyanide catalysts, which comprises the following steps:

(. alpha.) A partial amount of H-functional starter substance and/or of suspension medium which does not contain H-functional groups is initially loaded into the reactor, optionally together with DMC catalyst,

(gamma) metering alkylene oxide and optionally carbon dioxide into the reactor during the reaction,

characterized in that in step (. gamma.) lactide is metered into the reactor,

step (a):

in this process, a partial amount of H-functional starter substance and/or suspension medium which does not contain H-functional groups can first be loaded into the reactor. Subsequently, the DMC catalyst is optionally added to the reactor in the amount required for the polyaddition. The order of addition is not important here. It is also possible to initially charge the DMC catalyst and subsequently to charge a partial amount of H-functional starter substance into the reactor. Alternatively, it is also possible to first suspend the DMC catalyst in a portion of the amount of H-functional starter substance and then to charge this suspension into the reactor.

In a preferred embodiment of the present invention, the reactor is initially charged with the H-functional starter substance, optionally together with the DMC catalyst, in step (. alpha.) without first charging the reactor with a suspension medium which does not contain H functions.

The DMC catalyst is preferably used in such an amount that the catalyst content in the resulting reaction product is from 10 to 10000 ppm, more preferably from 20 to 5000 ppm, most preferably from 50 to 500 ppm.

In a preferred embodiment, an inert gas (e.g. argon or nitrogen), an inert gas-carbon dioxide mixture or carbon dioxide is introduced into the resulting mixture of (a) a partial amount of H-functional starter substance and (b) DMC catalyst at a temperature of from 90 ℃ to 150 ℃, more preferably from 100 ℃ to 140 ℃, and a reduced pressure (absolute) of from 10 mbar to 800 mbar, more preferably from 50 mbar to 200 mbar, is simultaneously applied.

In an alternative preferred embodiment, the resulting mixture of (a) partial amounts of H-functional starter substance and (b) DMC catalyst is subjected to an inert gas (for example argon or nitrogen), an inert gas-carbon dioxide mixture or carbon dioxide at least once, preferably three times, at a temperature of from 90 ℃ to 150 ℃, more preferably from 100 ℃ to 140 ℃, in the range from 1.5 bar to 10 bar (absolute), more preferably from 3 bar to 6 bar (absolute), and the overpressure is then reduced in each case to approximately 1 bar (absolute).

The DMC catalyst can be added in the form of a solid or as a suspension in a suspension medium which contains no H-functional groups, in an H-functional starter compound or in a mixture thereof.

In another preferred embodiment, in step (. alpha.),

(alpha-I) first a partial amount of H-functional starter substance and/or suspension medium is loaded, and

(α -II) bringing the partial amount of H-functional starter substance to a temperature of 50 ℃ to 200 ℃, preferably 80 ℃ to 160 ℃, more preferably 100 ℃ to 140 ℃, and/or reducing the pressure in the reactor to less than 500 mbar, preferably 5 mbar to 100 mbar, wherein optionally an inert gas stream (e.g. argon or nitrogen), an inert gas-carbon dioxide stream or a carbon dioxide stream is passed through the reactor,

wherein the DMC catalyst is added to the partial amount of H-functional starter substance in step (. alpha. -I) or immediately thereafter in step (. alpha. -II).

A fraction of the amount of H-functional starter substance used in (α) may comprise component K, preferably in an amount of at least 50 ppm, more preferably from 100 to 10000 ppm.

In a preferred embodiment, step (α) is carried out in the absence of lactide.

Step (β):

step (. beta.) serves to activate the DMC catalyst. This step can optionally be carried out under an inert gas atmosphere, under an atmosphere consisting of an inert gas-carbon dioxide mixture or under a carbon dioxide atmosphere. Activation means in the context of the present invention the step of adding a partial amount of alkylene oxide to the DMC catalyst suspension at a temperature of from 90 ℃ to 150 ℃ and subsequently interrupting the alkylene oxide addition, wherein, as a result of the subsequent exothermic chemical reaction, heat generation is observed which can lead to a temperature peak ("hot spot"), and as a result of the alkylene oxide and optionally CO₂A pressure drop was observed in the reactor. The process step of activation is carried out by reacting a partial amount of alkylene oxide, optionally in CO₂In the presence of a DMC catalyst until a period of heat generation has occurred. Optionally, it is possible to carry out a plurality of separate steps, optionally in CO₂Adding the partial amount of alkylene oxide to the DMC catalyst in the presence ofThe addition of alkylene oxide is interrupted in each case. In this case, the process step of activation comprises the step of optionally adding CO to a first partial amount of alkylene oxide₂In the presence of a DMC catalyst until a period of heat generation has occurred after the last partial amount of alkylene oxide has been added. Generally, a step of drying the DMC catalyst and optionally the H-functional starter substance at elevated temperature and/or under reduced pressure can be provided before the activation step, wherein optionally an inert gas is passed through the reaction mixture.

The metering in of the alkylene oxide (and optionally carbon dioxide) can in principle be effected in different ways. The metering can be started under vacuum or under a preselected pre-pressure (Vordruck). The pre-pressure is preferably established by introducing an inert gas (e.g. nitrogen or argon) or carbon dioxide, wherein the pressure (absolute) is from 5 mbar to 100 bar, preferably from 10 mbar to 50 bar, preferably from 20 mbar to 50 bar.

In a preferred embodiment, the amount of alkylene oxide used in the activation in step (β) is from 0.1 to 25.0 wt. -%, preferably from 1.0 to 20.0 wt. -%, more preferably from 2.0 to 16.0 wt. -%, based on the amount of H-functional starter substance used in step (α). The alkylene oxide can be added in one step or in portions in the form of a plurality of partial amounts. Preferably, after adding a partial amount of alkylene oxide, the addition of alkylene oxide is interrupted until heat generation occurs and not until then a next partial amount of alkylene oxide is added. Preference is also given to two-stage activation (step. beta.), where

(. beta.1) adding a first partial amount of alkylene oxide in a first activation stage under an inert gas atmosphere or under an atmosphere of carbon dioxide, and

(. beta.2) adding a second partial amount of alkylene oxide under an atmosphere of carbon dioxide in a second activation stage.

Step (y):

the metering in of the H-functional starter substance, alkylene oxide, lactide and optionally carbon dioxide can be carried out simultaneously or successively (in portions). Preferably, the H-functional starter substance is metered continuously into the reactor during the reaction and the alkylene oxide, lactide and optionally carbon dioxide are metered into the reactor simultaneously or successively (in portions) during the reaction. It is particularly preferred that the H-functional starter substance, alkylene oxide, lactide and carbon dioxide are metered simultaneously and continuously into the reactor during the reaction. For example, the total amount of carbon dioxide, the amount of H-functional starter substance and/or the amounts of alkylene oxide and lactide metered in step (γ) may be added in one portion or continuously. The term "continuous" as used herein may be defined as a mode of reactant addition such that the concentration of reactants effective for copolymerization is maintained, i.e., the metering may be carried out, for example, at a constant metering rate, at a variable metering rate, or in portions.

In the context of the present invention, the term "copolymerization" is understood to mean the polymerization of at least two different monomeric compounds, i.e. including the polymerization of three different monomers (commonly referred to as "trimerization") or the polymerization of four or more different monomers.

The CO can be increased or decreased gradually or stepwise during the addition of the alkylene oxide, lactide and/or H-functional starter substances₂The pressure is kept constant. Preferably, the total pressure is kept constant during the reaction by metering in additional carbon dioxide. The metering of the alkylene oxide and/or H-functional starter substance takes place simultaneously or successively with the metering of carbon dioxide.

The alkylene oxide and/or lactide may be metered in at a constant metering rate, or the metering rate may be increased or decreased gradually or stepwise, or the alkylene oxide and/or lactide may be added portionwise. Preferably, the alkylene oxide and/or lactide is added to the reaction mixture at a constant metering rate. If a plurality of alkylene oxides and/or lactides are used for the synthesis of the polyether ester carbonate polyols, the alkylene oxides and/or lactides can be metered in individually or as mixtures.

The addition of alkylene oxide and lactide is preferably carried out via separate metering points. However, it is also possible to meter in mixtures of alkylene oxide and lactide. The metering in of the alkylene oxide and the H-functional starter substance can take place simultaneously or successively in each case via separate metering in (addition) or via one or more metering in, where the alkylene oxide and the H-functional starter substance can be metered in individually or as a mixture. Random, alternating, block-wise or gradient polyether ester carbonate polyols can be synthesized by means and/or sequence of metered addition of H-functional starter substances, alkylene oxides, lactides and/or carbon dioxide.

In a preferred embodiment, the metering of the H-functional starter substance in step (γ) is terminated at a point in time before the addition of alkylene oxide and/or lactide.

Based on the calculated amount of carbon dioxide incorporated into the polyetherestercarbonate polyol, it is preferred to use an excess of carbon dioxide, since an excess of carbon dioxide is advantageous due to the reaction inertness of carbon dioxide. The amount of carbon dioxide can be determined by the total pressure under the respective reaction conditions. It has been found that the total pressure (absolute) which is advantageous for the copolymerization for preparing the polyetherestercarbonate polyols is from 0.01 to 120 bar, preferably from 0.1 to 110 bar, more preferably from 1 to 100 bar. The carbon dioxide may be supplied continuously or discontinuously. Depending on how fast the alkylene oxide is consumed and whether the product should contain optionally no CO₂The polyether block of (1). The amount of carbon dioxide (given as pressure) can likewise be varied during the alkylene oxide addition. CO 2₂It can also be added in solid form to the reactor and then converted into the gaseous, dissolved, liquid and/or supercritical state under the selected reaction conditions.

A preferred embodiment of the process according to the invention is characterized in particular in that the total amount of H-functional starter substance is added in step (. gamma.). This addition can be carried out at a constant metering rate, at a variable metering rate or in portions.

It has also been found for the process of the present invention that the copolymerization (step (. gamma.) for the preparation of the polyetherestercarbonate polyols is advantageously carried out at from 50 ℃ to 150 ℃, preferably from 60 ℃ to 145 ℃, more preferably from 70 ℃ to 140 ℃, very particularly preferably from 90 ℃ to 130 ℃. If a temperature below 50 ℃ is set, the reaction generally becomes very slow. At temperatures above 150 ℃, the amount of unwanted by-products increases dramatically.

The metered addition of the alkylene oxide, lactide, H-functional starter substance and DMC catalyst can be effected via separate or common metering points. In a preferred embodiment, the alkylene oxide and the H-functional starter substance are supplied continuously to the reaction mixture via separate metering points. The H-functional starter substance can be added to the reactor in the form of a continuous metered addition or in portions.

Steps (α), (β) and (γ) may be carried out in the same reactor, or may each be carried out separately in a different reactor. Particularly preferred reactor types are: tubular reactor, stirred tank, loop reactor.

The polyether ester carbonate polyol can be prepared in a stirred tank, wherein the stirred tank is cooled by the reactor jacket, internal cooling surfaces and/or cooling surfaces within the pumped circulation loop, depending on the embodiment and mode of operation. Particular attention should be paid to the metering rate of the alkylene oxide both in semibatchwise applications, in which the product is removed only after the end of the reaction, and in continuous applications, in which the product is removed continuously. The rate should be adjusted so that the alkylene oxide reacts sufficiently rapidly despite the carbon dioxide inhibition. The concentration of free alkylene oxide in the reaction mixture during the activation step (step β) is preferably > 0 wt. -% to 100 wt. -%, more preferably > 0 wt. -% to 50 wt. -%, most preferably > 0 wt. -% to 20 wt. -%, in each case based on the weight of the reaction mixture. The concentration of free alkylene oxide in the reaction mixture during the reaction (step γ) is preferably > 0 to 40 wt. -%, more preferably > 0 to 25 wt. -%, most preferably > 0 to 15 wt. -%, in each case based on the weight of the reaction mixture.

In a preferred embodiment, the activated DMC catalyst-suspension medium mixture obtained from steps (α) and (β) is further reacted in the same reactor with alkylene oxide, an H-functional starter substance and carbon dioxide. In another preferred embodiment, the activated DMC catalyst-suspension medium mixture obtained from steps (α) and (β) is further reacted with alkylene oxide, an H-functional starter substance and carbon dioxide in a further reaction vessel, for example a stirred tank, a tubular reactor or a loop reactor.

If the reaction is carried out in a tubular reactor, the activated catalyst-suspension medium mixture obtained from steps (. alpha.) and (. beta.), the H-functional starter substance, the alkylene oxide and carbon dioxide are pumped continuously through the tube. The molar ratio of the co-reactants varies depending on the desired polymer. In a preferred embodiment, the carbon dioxide is metered in here in its liquid or supercritical form in order to achieve optimum miscibility of the components. It is advantageous to install mixing elements for better thorough mixing of its reactants, or mixer-heat exchanger elements that improve both thorough mixing and heat rejection, as for example sold by Ehrfeld Mikrotechnik BTS GmbH.

The polyether ester carbonate polyols can likewise be prepared using a loop reactor. These generally include reactors with material recirculation, for example injection loop reactors which can also be operated continuously, or tubular reactors designed in the form of a loop with means suitable for circulating the reaction mixture, or loops of a plurality of tubular reactors connected in series. The use of a loop reactor is therefore particularly advantageous, since backmixing can be achieved here so that the concentration of free alkylene oxide in the reaction mixture can be kept in an optimum range, preferably from > 0% to 40% by weight, more preferably from > 0% to 25% by weight, most preferably from > 0% to 15% by weight (based in each case on the weight of the reaction mixture).

Preferably, the polyether ester carbonate polyols are prepared in a continuous process comprising continuous copolymerization and continuous addition of H-functional starter substances.

The subject of the invention is therefore also a process in which, in step (γ), the H-functional starter substance, alkylene oxide, lactide and DMC catalyst are metered continuously into a reactor in the presence of carbon dioxide ("copolymerization"), and in which the resulting reaction mixture (comprising the reaction product) is removed continuously from the reactor. The DMC catalyst is preferably added here continuously in step (. gamma.) in the form of a suspension in an H-functional starter substance.

For example, for a continuous process for preparing polyether ester carbonate polyols in steps (. alpha.) and (. beta.), an activated DMC catalyst-suspension medium mixture is prepared, and then in step (. gamma.),

(. gamma.1) separately metering in partial amounts of H-functional starter substance, alkylene oxide and carbon dioxide to initiate copolymerization, and

(. gamma.2) during the course of the copolymerization, the remaining amounts of DMC catalyst, H-functional starter substance, alkylene oxide and lactide are each metered in continuously in the presence of carbon dioxide, the reaction mixture obtained being removed continuously from the reactor at the same time.

In step (. gamma.) the DMC catalyst is preferably added in suspended form in the H-functional starter substance, wherein the amount is preferably chosen such that the DMC catalyst content in the resulting reaction product is from 10 to 10000 ppm, more preferably from 20 to 5000 ppm, most preferably from 50 to 500 ppm.

Preferably, steps (α) and (β) are carried out in a first reactor, and the resulting reaction mixture is then transferred to a second reactor for the copolymerization of step (γ). It is also possible to carry out steps (. alpha.,. beta.) and (. gamma.) in one reactor.

It has also been found that the process of the invention can be used for preparing large amounts of polyether ester carbonate polyols, in which firstly a DMC catalyst which is activated according to steps (α) and (β) in a suspension medium is used and the DMC catalyst which has not been previously activated is added during copolymerization (γ).

A particularly advantageous feature of this preferred embodiment of the invention is therefore the possibility of using the unactivated "fresh" DMC catalyst as a part of the amount of DMC catalyst continuously added in step (γ). Activation of the DMC catalyst, carried out analogously to step (β), involves not only additional operator attention, which leads to increased manufacturing costs, but also the need for a pressure reaction vessel, which also leads to increased capital costs for constructing a corresponding production plant. "fresh" catalyst is defined herein as an unactivated DMC catalyst in solid form or in suspended form in a suspension medium or H-functional starter substance. The ability of the present process to use fresh, unactivated DMC catalyst in step (γ) enables significant savings in the commercial preparation of polyether ester carbonate polyols and is a preferred embodiment of the present invention.

The term "continuous" as used herein can be defined as a mode of addition of the associated catalyst or reactant that maintains a substantially continuous effective concentration of the DMC catalyst or reactant. The catalyst may be fed in a truly continuous manner or in relatively closely spaced increments. Continuous addition of starter can likewise be effected in a truly continuous manner or incrementally. Without departing from the present method, the DMC catalyst or reactant is added incrementally such that the concentration of the added material is reduced to substantially 0 for a period of time before the next incremental addition. However, it is preferred to maintain the DMC catalyst concentration at essentially the same concentration for the major portion of the course of the continuous reaction and to have the starter substance present for the major portion of the copolymerization process. However, incremental addition of DMC catalyst and/or reactant that does not significantly affect the product properties is "continuous" in the sense that the term is used herein. A recirculation loop may for example be provided in which a portion of the reaction mixture is recirculated to a previous location in the process, thereby eliminating discontinuities caused by incremental additions.

Step (delta)

Optionally in step (δ), the reaction mixture continuously removed in step (γ), typically having an alkylene oxide content of from 0.05 to 10 wt.%, can be transferred to a post-reactor, in which the content of free alkylene oxide in the reaction mixture is reduced to less than 0.05 wt.% by post-reaction. The post-reactor used may be, for example, a tubular reactor, a loop reactor or a stirred tank.

Preferably, the pressure in this latter reactor is the same pressure as in the reaction apparatus in which reaction step (. gamma.) is carried out. However, it is also possible to select a higher or lower pressure in the downstream reactor. In another preferred embodiment, carbon dioxide is released completely or partially after the reaction step (. gamma.) and the downstream reactor is operated at standard pressure or slightly overpressure. The temperature in the downstream reactor is preferably from 50 ℃ to 150 ℃, more preferably from 80 ℃ to 140 ℃.

Suitable suspension media which do not contain H functional groups are all polar aprotic, weakly polar aprotic and nonpolar aprotic solvents which do not contain H functional groups. The suspension medium used may also be a mixture of two or more of these suspension media. The following polar aprotic solvents are mentioned here by way of example: 4-methyl-2-oxo-1, 3-dioxolane (hereinafter also referred to as cyclic propylene carbonate or cPC), 1, 3-dioxolan-2-one (hereinafter also referred to as cyclic ethylene carbonate or cEC), acetone, methyl ethyl ketone, acetonitrile, nitromethane, dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone. One class of aprotic and weakly polar aprotic solvents includes, for example, ethers such as dioxane, diethyl ether, methyl tert-butyl ether and tetrahydrofuran, esters such as ethyl acetate and butyl acetate, hydrocarbons such as pentane, n-hexane, benzene and alkylated benzene derivatives (e.g., toluene, xylene, ethylbenzene) and chlorinated hydrocarbons such as chloroform, chlorobenzene, dichlorobenzene and carbon tetrachloride. Preferred as suspension media are 4-methyl-2-oxo-1, 3-dioxolane, 1, 3-dioxolan-2-one, toluene, xylene, ethylbenzene, chlorobenzene and dichlorobenzene as well as mixtures of two or more of these suspension media; particular preference is given to 4-methyl-2-oxo-1, 3-dioxolane and 1, 3-dioxolan-2-one or mixtures of 4-methyl-2-oxo-1, 3-dioxolane and 1, 3-dioxolan-2-one.

In the context of the present invention, lactide is a cyclic compound containing two or more ester bonds in the ring, preferably a compound of formula (II),

wherein R1, R2, R3 and R4 independently of one another represent hydrogen, a linear or branched C1 to C22 alkyl group optionally containing heteroatoms, a linear or branched, mono-or polyunsaturated C1 to C22 alkenyl group optionally containing heteroatoms, or an optionally mono-or polysubstituted C6 to C18 aryl group optionally containing heteroatoms, or may be a member of a saturated or unsaturated 4-to 7-membered ring or polycyclic system optionally containing heteroatoms and/or ether groups,

and n and o are, independently of one another, an integer greater than or equal to 1, preferably 1,2, 3 or 4,

and R1 and R2 in the repeating unit (n >1) and R3 and R4 in the repeating unit (o >1) may each be different.

Preferred compounds of the formula (II) are 1, 4-dioxane-2, 5-dione, (S, S) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, (R, R) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, meso-3, 6-dimethyl-1, 4-dioxane-2, 5-dione and 3-methyl-1, 4-dioxane-2, 5-dione, 3-hexyl-6-methyl-1, 4-dioxane-2, 5-dione, 3, 6-di (but-3-en-1-yl) -1, 4-dioxane-2, 5-dione (in each case including the optically active form). (S, S) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione is particularly preferred.

The amount of lactide used in the process of the present invention is preferably from 5 to 40% by weight, more preferably from 5 to 30% by weight, particularly preferably from 10 to 30% by weight, based in each case on the total amount of alkylene oxide used.

The process of the present invention can generally use alkylene oxides having from 2 to 24 carbon atoms as alkylene oxide. Alkylene oxides having from 2 to 24 carbon atoms are, for example, ethylene oxide, propylene oxide, 1-butylene oxide, 2, 3-butylene oxide, 2-methyl-1, 2-propylene oxide (isobutylene oxide), 1-pentylene oxide, 2, 3-pentylene oxide, 2-methyl-1, 2-butylene oxide, 3-methyl-1, 2-butylene oxide, 1-hexylene oxide, 2, 3-hexylene oxide, 3, 4-hexylene oxide, 2-methyl-1, 2-pentylene oxide, 4-methyl-1, 2-pentylene oxide, 2-ethyl-1, 2-butylene oxide, 1-heptylene oxide, 1-octylene oxide, 1-cyclononane, 1-decylene oxide, 1-cyclohexylene oxide, 1-epoxyundecane, 1-epoxydodecane, 4-methyl-1, 2-epoxypentane, butadiene monooxide, isoprene monooxide, epoxycyclopentane, epoxycyclohexane, epoxycycloheptane, epoxycyclooctane, styrene oxide, methylstyrene oxide, pinene oxide, mono-or poly-epoxidized fats (in the form of mono-, di-and tri-esters of glycerol), epoxidized fatty acids, C of epoxidized fatty acids₁-C₂₄Esters, epichlorohydrin, glycidol and glycidyl derivatives such as methyl glycidyl ether, ethyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, glycidyl methacrylate and epoxy-functional alkoxysilanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-Glycidoxypropyl-methyl-dimethoxysilane, 3-glycidoxypropyl-ethyl-diethoxysilane, and 3-glycidoxypropyltriisopropoxysilane. Alkylene oxides which are preferably used are ethylene oxide and/or propylene oxide, in particular propylene oxide.

Suitable H-functional starter substances ("starters") which can be used are compounds having hydrogen atoms which are active for alkoxylation and having a molar mass of from 18 to 4500 g/mol, preferably from 60 to 500 g/mol, more preferably from 62 to 182 g/mol. The possibility of using starter substances having a low molar mass is a clear advantage over the use of oligomeric starters prepared by means of prior alkoxylation. In particular, economic feasibility is achieved by omitting a separate alkoxylation process.

Groups reactive for alkoxylation and having active hydrogen atoms are, for example, -OH, -NH₂(primary amine), -NH- (secondary amine), -SH and-CO₂H, preferably-OH and-NH₂More preferably-OH. The H-functional starter substances used are, for example, selected from the group consisting of mono-or polyols, polyamines, polythiols, aminoalcohols, thiol-containing (Thioalkohol), hydroxyesters, polyether polyols, polyester polyols, polyether ether polyols, polycarbonate polyols, polycarbonates, polyethyleneimines, polyetheramines, polytetrahydrofuranes (for example PolyTHF from BASF), polytetrahydrofuranamines, polyether thiols, polyacrylate polyols, castor oil, glycerol mono-or diesters of ricinoleic acid, glycerol monoesters of fatty acids, chemically modified glycerol mono-, di-and/or triesters of fatty acids, and fatty acid C-triglycerides containing an average of at least 2 OH groups per molecule₁-C₂₄One or more compounds of an alkyl ester. Fatty acids C containing an average of at least 2 OH groups per molecule₁-C₂₄Alkyl esters are, for example, Lupranol Balance (from BASF AG), Merginol type (from Hobum Oleochemicals GmbH), Sovermol type (from Cognis Deutschland GmbH)&Co, KG Corp.) and Soyol TM type (from USSC Co.).

Useful monofunctional initiator materials include alcohols, amines, thiols, and carboxylic acids. Useful monofunctional alcohols include: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 3-buten-1-ol, 3-butyn-1-ol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, propargyl alcohol, 2-methyl-2-propanol, 1-tert-butoxy-2-propanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, phenol, 2-hydroxybiphenyl, 2-hydroxy-ethyl-1-ol, 2-butanol, 3-methyl-2-propanol, 1-tert-butoxy-2-propanol, 1-pentanol, 2-pentanol, 3-hexanol, 2-hexanol, 1-heptanol, 2-hydroxy-biphenyl, 2-butanol, or the like, 2-butanol, or the like, 3-hydroxybiphenyl, 4-hydroxybiphenyl, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine. Useful monofunctional amines include: butylamine, tert-butylamine, pentylamine, hexylamine, aniline, aziridine, pyrrolidine, piperidine, morpholine. The monofunctional thiols used may be: ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 3-methyl-1-butanethiol, 2-butene-1-thiol, thiophenol. Monofunctional carboxylic acids include: formic acid, acetic acid, propionic acid, butyric acid, fatty acids such as stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, acrylic acid.

Examples of polyols suitable as H-functional starter substances include diols (e.g. ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 4-butenediol, 1, 4-butynediol, neopentyl glycol, 1, 5-pentanediol, methylpentanediols (e.g. 3-methyl-1, 5-pentanediol), 1, 6-hexanediol, 1, 8-octanediol, 1, 10-decanediol, 1, 12-dodecanediol, bis- (hydroxymethyl) -cyclohexane (e.g. 1, 4-bis- (hydroxymethyl) cyclohexane), triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol); trihydric alcohols (e.g., trimethylolpropane, glycerol, trishydroxyethyl isocyanurate, castor oil); tetrahydric alcohols (e.g., pentaerythritol); polyols (e.g., sorbitol, hexitols, sucrose, starch hydrolysates, cellulose hydrolysates, hydroxy-functionalized fats and oils, especially castor oil) and all modifications of these aforementioned alcohols with varying amounts of epsilon-caprolactone.

H-functional starter substances can also be selected from substances having a molecular weight M of from 18 to 4500 g/mol_nAnd a functionality of 2 to 3. Preferred are polyether polyols made up of repeating ethylene oxide and propylene oxide units,it preferably has a content of propylene oxide units of from 35% to 100%, more preferably from 50% to 100%. These may be random, gradient, alternating or block copolymers of ethylene oxide and propylene oxide.

The H-functional starter substance can also be selected from the substance class of polyester polyols. An at least difunctional polyester is used as the polyester polyol. The polyester polyols are preferably composed of alternating acid and alcohol units. The acid component used is, for example, succinic acid, maleic anhydride, adipic acid, phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride or mixtures of the acids and/or anhydrides. The alcohol component used is, for example, ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 4-bis- (hydroxymethyl) cyclohexane, diethylene glycol, dipropylene glycol, trimethylolpropane, glycerol, pentaerythritol or mixtures of the alcohols mentioned. If a binary or polyhydric polyether polyol is used as the alcohol component, polyester ether polyols are obtained which likewise can serve as starter substances for the preparation of polyether ester carbonate polyols.

Furthermore, the H-functional starter substances used may be, for example, polycarbonate diols prepared by reaction of phosgene, dimethyl carbonate, diethyl carbonate or diphenyl carbonate and difunctional alcohols or polyester polyols or polyether polyols. Examples of polycarbonates can be found, for example, in EP-A1359177.

In another embodiment of the present invention, polyetherestercarbonate polyols can be used as H-functional starter substances. Particularly useful are the polyether ester carbonate polyols obtainable by the process of the invention described herein. For this purpose, these polyetherestercarbonate polyols used as H-functional starter substances are prepared beforehand in a separate reaction step.

The H-functional starter substances generally have a functionality (i.e.the number of H atoms per molecule which are active for polymerization) of from 1 to 8, preferably 2 or 3. The H-functional starter substances are used on their own or as a mixture of at least two H-functional starter substances.

H-functional starter substances are particularly preferably one or more compounds selected from the group consisting of ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 4-diol, pentane-1, 5-diol, 2-methylpropane-1, 3-diol, neopentyl glycol, hexane-1, 6-diol, octane-1, 8-diol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol and polyether polyols having a molecular weight Mn of from 150 to 4500 g/mol and a functionality of from 2 to 3.

Polyether ester carbonate polyols are prepared by the catalytic addition of carbon dioxide, lactide and alkylene oxide to an H-functional starter substance. In the context of the present invention, "H-functional" is understood to mean the number of H atoms per molecule of starter substance which are active with respect to alkoxylation.

DMC catalysts for the homopolymerization of alkylene oxides are known in principle from the prior art (see, for example, U.S. Pat. No. 3, 3404109, U.S. Pat. No. 3, 3829505, U.S. Pat. No. 3, 3941849 and U.S. Pat. No. 5158922). DMC catalysts such as those described in U.S. Pat. No. 4, 5470813, EP-A700949, EP-A743093, EP-A761708, WO 97/40086, WO 98/16310 and WO 00/47649 have very high activity and enable polyether ester carbonate polyols to be prepared at very low catalyst concentrations, so that it is generally no longer necessary to separate the catalyst from the finished product. Typical examples are the highly active DMC catalysts described in EP-A700949, which contain not only double metal cyanide compounds, for example zinc hexacyanocobaltate (III), and organic complexing ligands, for example tert-butanol, but also polyethers having a number average molecular weight of more than 500 g/mol.

The DMC catalysts according to the invention are preferably obtained by the following process

(i) In a first step an aqueous solution of a metal salt is reacted with an aqueous solution of a metal cyanide salt in the presence of one or more organic complexing ligands, such as ethers or alcohols,

(ii) wherein in a second step the solids are separated from the suspension obtained from (i) by known techniques such as centrifugation or filtration,

(iii) wherein the separated solid is optionally washed with an aqueous solution of the organic complexing ligand in a third step (e.g.by resuspension and subsequent re-separation by filtration or centrifugation),

(iv) wherein the resulting solid is subsequently dried, optionally after powdering, at a temperature of typically 20-120 ℃ and a pressure of typically 0.1 mbar to standard pressure (1013 mbar),

and wherein in the first step or immediately after precipitation of the double metal cyanide compound (second step), one or more organic complexing ligands and optionally further complex-forming components are added, preferably in excess, based on the double metal cyanide compound.

The double metal cyanide compounds contained in the DMC catalysts according to the invention are reaction products of water-soluble metal salts and water-soluble metal cyanide salts.

For example, an aqueous solution of zinc chloride (preferably in excess based on the metal cyanide salt, e.g., potassium hexacyanocobaltate) and potassium hexacyanocobaltate are mixed and dimethoxyethane (glyme) or tert-butanol (preferably in excess based on zinc hexacyanocobaltate) is then added to the suspension formed.

The metal salts suitable for preparing the double metal cyanide compounds preferably have the general formula (III)

Wherein

M is selected from the metal cations Zn²⁺、Fe²⁺、Ni²⁺、Mn²⁺、Co²+、Sr²⁺、Sn²⁺、Pb²⁺And Cu²⁺(ii) a M is preferably Zn²⁺、Fe² ⁺、Co²⁺Or Ni²⁺，

X is one or more (i.e. different) anions, preferably an anion selected from the group consisting of halide (i.e. fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and nitrate;

when X = sulfate, carbonate or oxalate, n is 1, and

when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, n is 2,

or a suitable metal salt having the general formula (IV)

Wherein

M is selected from the metal cations Fe³⁺、Al³⁺、Co³⁺And Cr³⁺，

when X = sulfate, carbonate or oxalate, r is 2, and

when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, r is 1,

or a suitable metal salt having the formula (V)

Wherein

M is selected from metal cation Mo⁴⁺、V⁴⁺And W⁴⁺，

when X = sulfate, carbonate or oxalate, s is 2, and

when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, s is 4,

or suitable metal salts have the general formula (VI)

Wherein

M is selected from metal cation Mo⁶⁺And W⁶⁺，

when X = sulfate, carbonate or oxalate, t is 3, and

when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, t is 6,

examples of suitable metal salts are zinc chloride, zinc bromide, zinc iodide, zinc acetate, zinc acetylacetonate, zinc benzoate, zinc nitrate, iron (II) sulfate, iron (II) bromide, iron (II) chloride, iron (III) chloride, cobalt (II) thiocyanate, nickel (II) chloride and nickel (II) nitrate. Mixtures of different metal salts may also be used.

The metal cyanide salts suitable for preparing double metal cyanide compounds preferably have the general formula (VII)

Wherein

M' is selected from one or more metal cations of Fe (II), Fe (III), Co (II), Co (III), Cr (II), Cr (III), Mn (II), Mn (III), Ir (III), Ni (II), Rh (III), Ru (II), V (IV) and V (V); m' is preferably one or more metal cations selected from Co (II), Co (III), Fe (II), Fe (III), Cr (III), Ir (III) and Ni (II),

y is selected from alkali metals (i.e. Li)⁺、Na⁺、K⁺、Rb⁺) And alkaline earth metals (i.e., Be)²⁺、Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺) One or more ofThe cation of the seed metal is selected from the group consisting of,

a is selected from one or more anions of halide (i.e. fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, azide, oxalate or nitrate, and

a. b and c are integers, wherein the values of a, b and c are selected to ensure electroneutrality of the metal cyanide salt; a is preferably 1,2, 3 or 4; b is preferably 4, 5 or 6; c preferably has a value of 0.

Examples of suitable metal cyanide salts are sodium hexacyanocobaltate (III), potassium hexacyanoferrate (II), potassium hexacyanoferrate (III), calcium hexacyanocobaltate (III) and lithium hexacyanocobaltate (III).

Preferred double metal cyanide compounds comprised in the DMC catalysts of the present invention are compounds of the general formula (VIII)

Wherein M is as defined in formulae (III) to (VI), and

m' is as defined in formula (VII), and

x, x', y and z are integers and are selected to ensure electroneutrality of the double metal cyanide compound.

It is preferable that

x = 3, x' = 1, y = 6 and z = 2,

m = Zn (II), Fe (II), Co (II) or Ni (II), and

m' = Co (III), Fe (III), Cr (III) or Ir (III).

Examples of suitable double metal cyanide compounds a) are zinc hexacyanocobaltate (III), zinc hexacyanocoridate (III), zinc hexacyanoferrate (III) and cobalt (II) hexacyanocobaltate (III). Further examples of suitable double metal cyanide compounds can be found, for example, in US 5158922 (column 8, lines 29-66). Particular preference is given to using zinc hexacyanocobaltate (III).

Organic complexing ligands added in the preparation of DMC catalysts are disclosed, for example, in US 5158922 (see, in particular, column 6, lines 9 to 65), US 3404109, US 3829505, US 3941849, EP-A700949, EP-A761708, JP 4145123, US 5470813, EP-A743093 and WO-A97/40086. For example, the organic complexing ligands used are water-soluble organic compounds having heteroatoms, such as oxygen, nitrogen, phosphorus or sulfur, which can form complexes with double metal cyanide compounds. Preferred organic complexing ligands are alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, thioethers and mixtures thereof. Particularly preferred organic complexing ligands are aliphatic ethers (e.g.dimethoxyethane), water-soluble aliphatic alcohols (e.g.ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 2-methyl-3-buten-2-ol and 2-methyl-3-butyn-2-ol), compounds containing aliphatic or cycloaliphatic ether groups and aliphatic hydroxyl groups (e.g.ethylene glycol mono-tert-butyl ether, diethylene glycol mono-tert-butyl ether, tripropylene glycol monomethyl ether and 3-methyl-3-oxetanemethanol). The most preferred organic complexing ligand is selected from one or more of dimethoxyethane, t-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-t-butyl ether and 3-methyl-3-oxetanemethanol.

The preparation of the DMC catalysts according to the present invention optionally uses a catalyst selected from the group consisting of polyethers, polyesters, polycarbonates, polyalkylene glycol sorbitan esters, polyalkylene glycol glycidyl ethers, polyacrylamides, poly (acrylamide-co-acrylic acid), polyacrylic acids, poly (acrylic acid-co-maleic acid), polyacrylonitrile, polyalkyl acrylates, polyalkyl methacrylates, polyvinyl methyl ethers, polyvinyl ethyl ethers, polyvinyl acetates, polyvinyl alcohols, poly-N-vinylpyrrolidone, poly (N-vinylpyrrolidone-co-acrylic acid), polyvinyl methyl ketones, poly (4-vinylphenol), poly (acrylic acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic acid and maleic anhydride copolymers, hydroxyethylcellulose and polyacetals, poly (ethylene glycol) glycidyl ethers, poly (ethylene glycol methyl ethers), poly (ethylene glycol) ethers, poly (ethylene glycol methyl ethers), poly (ethyleneethers), poly (, Or one or more complex-forming components of the class of compounds of glycidyl ethers, glycosides, carboxylic esters of polyhydric alcohols, gallic acid (Gallens ä ure) or salts, esters or amides thereof, cyclodextrins, phosphorus compounds, esters of alpha, beta-unsaturated carboxylic acids or ionic surface-or interface-active compounds.

Preferably, in the DMC catalyst preparation according to the invention, an aqueous solution of a metal salt (e.g. zinc chloride), which is preferably used in a stoichiometric excess (at least 50 mol%) based on the metal cyanide salt (i.e. a molar ratio of metal salt to metal cyanide salt of at least 2.25:1.00), and a metal cyanide salt (e.g. potassium hexacyanocobaltate) is reacted in a first step in the presence of an organic complexing ligand (e.g. tert-butanol) to form a suspension comprising a double metal cyanide compound (e.g. zinc hexacyanocobaltate), water, excess metal salt and the organic complexing ligand.

Such organic complexing ligands can be present here in an aqueous solution of the metal salt and/or of the metal cyanide salt or added directly to the suspension obtained after precipitation of the double metal cyanide compound. It has proven advantageous to mix the metal salt and the aqueous metal cyanide salt solution with the organic complexing ligand by vigorous stirring. Optionally, the suspension formed in the first step is subsequently treated with additional complex-forming components. The complex-forming component is preferably used here in the form of a mixture with water and an organic complexing ligand. The preferred method for carrying out the first step, i.e. the preparation of the suspension, is carried out by using a mixing nozzle, more preferably using a jet disperser as described in WO-a 01/39883.

In a second step, the solid (i.e. the precursor of the catalyst of the invention) is separated from the suspension by known techniques, such as centrifugation or filtration.

In a preferred embodiment variant, the isolated solid is subsequently washed in a third process step with an aqueous solution of the organic complexing ligand (for example by resuspension and subsequent re-isolation by filtration or centrifugation). It is thereby possible to remove, for example, water-soluble by-products, such as potassium chloride, from the catalyst according to the invention. The amount of organic complexing ligand in the aqueous wash solution is preferably from 40 to 80 wt.%, based on total solution.

Optionally, 0.5 to 5 wt.%, preferably based on the total solution, of further complex-forming components are added to the aqueous washing solution in a third step.

It is also advantageous to wash the separated solids more than once. Preferably, in the first washing step (iii-1), an aqueous solution of the unsaturated alcohol is used for washing (for example by resuspension and subsequent re-separation by filtration or centrifugation) to thereby remove, for example, water-soluble by-products, such as potassium chloride, from the catalyst according to the invention. The amount of unsaturated alcohol in the aqueous washing solution is particularly preferably from 40% to 80% by weight, based on the total solution of the first washing step. In a further washing step (iii-2), the first washing step is repeated one or more times, preferably 1 to 3 times, or preferably a non-aqueous solution, for example a mixture or solution of the unsaturated alcohol and the further complex-forming component (preferably 0.5 to 5% by weight, based on the total amount of washing solution in step (iii-2)), is used as washing solution and the solid is washed one or more times, preferably 1 to 3 times, therewith.

The isolated and optionally washed solid can then be dried, optionally after powdering, at a temperature of 20-100 ℃ and a pressure of 0.1 mbar to standard pressure (1013 mbar).

A preferred process for separating the DMC catalyst according to the invention from the suspension by filtration, cake washing and drying is described in WO-A01/80994.

Another subject of the invention is a polyetherestercarbonate polyol obtainable by the process of the invention.

The polyetherestercarbonate polyols obtained according to the present invention have a functionality of, for example, at least 1, preferably from 1 to 8, more preferably from 1 to 6, most preferably from 2 to 4. The molecular weight is preferably from 400 to 10000 g/mol, more preferably from 500 to 6000 g/mol.

The polyetherestercarbonate polyols obtainable by the process of the present invention have a low content of by-products and a low viscosity and can be processed without difficulty, in particular by reaction with di-and/or polyisocyanates, to give polyurethanes, in particular polyurethane flexible foams, for example polyurethane flexible slabstock foams and polyurethane flexible molded foams. For polyurethane applications, preference is given to using polyetherestercarbonate polyols based on H-functional starter substances having a functionality of at least 2. Furthermore, the polyether ester carbonate polyols obtainable by the process according to the invention can also be used in applications such as washing and cleaning composition formulations, drilling fluids, fuel additives, ionic and nonionic surfactants, lubricants, technical chemicals for paper or textile manufacture or cosmetic formulations. The person skilled in the art knows that, depending on the respective field of application, the polyetherestercarbonate polyols to be used must meet certain material properties, such as molecular weight, viscosity, functionality and/or hydroxyl number.

In a first embodiment, the present invention relates to a process for preparing polyether ester carbonate polyols by the catalytic addition of alkylene oxides and carbon dioxide onto H-functional starter substances in the presence of double metal cyanide catalysts, which process comprises the steps of:

characterized in that lactide is metered into the reactor in step (. gamma.).

In a second embodiment, the invention relates to a process according to the first embodiment, characterized in that step (α) is carried out in the absence of lactide.

In a third embodiment, the present invention relates to a process according to the 1 st or 2 nd embodiment, characterized in that lactide is used in an amount of 5 to 40 wt. -%, based on the total amount of alkylene oxide used.

In a fourth embodiment, the present invention relates to a process according to the 1 st or 2 nd embodiment, characterized in that lactide is used in an amount of 10 to 30 wt. -%, based on the total amount of alkylene oxide used.

In a fifth embodiment, the present invention is directed to the method according to any one of embodiments 1 to 4, characterized in that, after step (α),

(β) adding a partial amount of alkylene oxide to the mixture from step (α) at a temperature of from 90 ℃ to 150 ℃ and subsequently interrupting the addition of alkylene oxide compound and/or lactide, wherein step (β) is in particular carried out under an inert gas atmosphere, under an inert gas-carbon dioxide mixture atmosphere or under a carbon dioxide atmosphere.

In a sixth embodiment, the present invention relates to a process according to any one of embodiments 1 to 5, characterized in that in step (γ) the H-functional starter substance, alkylene oxide and lactide are continuously metered into the reactor in the presence of carbon dioxide.

In a seventh embodiment, the present invention relates to a process according to any one of embodiments 1 to 6, characterized in that the metering of the H-functional starter substance is terminated in step (γ) at a point in time before the addition of alkylene oxide and/or lactide.

In an eighth embodiment, the present invention relates to a process according to any one of embodiments 1 to 7, characterized in that in step (γ) H-functional starter substance, alkylene oxide, lactide and double metal cyanide catalyst are metered continuously into the reactor and the resulting reaction mixture is removed continuously from the reactor.

In a ninth embodiment, the present invention relates to a process according to the 8 th embodiment, characterized in that the double metal cyanide catalyst is continuously added in suspended form in the H-functional starter substance.

In a tenth embodiment, the invention relates to a process according to the 8 th or 9 th embodiment, characterized in that in step (δ) downstream of step (γ), the reaction mixture having an alkylene oxide content of from 0.05 to 10% by weight which is continuously removed in step (γ) is transferred to a post-reactor and a post-reaction is carried out therein, thereby reducing the content of free alkylene oxide in the reaction mixture to less than 0.05% by weight.

In an eleventh embodiment, the invention relates to a process according to any one of embodiments 1 to 10, characterized in that the lactide used is at least one compound of formula (II),

and n and o independently of one another represent an integer of 1 or more, preferably 1,2, 3 or 4, and R1 and R2 in the repeating unit (n >1) and R3 and R4 in the repeating unit (o >1) may be different in each case.

In a twelfth embodiment the invention relates to a process according to any one of the embodiments 1 to 10, characterized in that the lactide is selected from the group consisting of 1, 4-dioxane-2, 5-dione, (S, S) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, (R, R) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, meso-3, 6-dimethyl-1, 4-dioxane-2, 5-dione and 3-methyl-1, 4-dioxane-2, 5-dione, 3-hexyl-6-methyl-1, 4-dioxane-2, at least one compound of 5-dione, 3, 6-di (but-3-en-1-yl) -1, 4-dioxane-2, 5-dione (in each case including the optically active form).

In a thirteenth embodiment, the invention relates to a process according to any one of embodiments 1 to 12, characterized in that the H-functional initiator substance is selected from the group consisting of alcohols, amines, thiols, amino alcohols, thiol-containing, hydroxyl esters, polyether polyols, polyester ether polyols, polycarbonate polyols, polyether carbonate polyols, polyethyleneimines, polyether amines, polytetrahydrofuran, polyether thiols, polyacrylate polyols, castor oil, monoglycerides or diglycerides of ricinoleic acid, monoglycerides of fatty acids, chemically modified monoglycerides, diglycerides and/or triglycerides of fatty acids and C1-C24 alkyl esters of fatty acids containing an average of at least 2 OH groups per molecule.

In a fourteenth embodiment, the present invention relates to a process according to any one of embodiments 1 to 12, characterized in that the H-functional starter substance is selected from the group consisting of ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 4-diol, pentane-1, 5-diol, 2-methylpropane-1, 3-diol, neopentyl glycol, hexane-1, 6-diol, octane-1, 8-diol, diethylene glycol, or mixtures thereofPropylene glycol, glycerol, trimethylolpropane, di-and trifunctional polyether polyols or mixtures thereof, wherein the polyether polyols are formed from di-or tri-H-functional starter substances and propylene oxide or di-or tri-H-functional starter substances, propylene oxide and ethylene oxide and in particular have a molecular weight M of 62 to 4500 g/mol_nAnd a functionality of 2 to 3.

Examples

Raw materials

PET-1: a difunctional poly (oxypropylene) polyol having an OH number of 112 mgKOH/g

PO: propylene oxide

Lactide: 3, 6-dimethyl-1, 4-dioxane-2, 5-dione

MSA: maleic anhydride

The DMC catalyst was prepared according to example 6 of WO 01/80994A 1.

Method

In propylene oxide, lactide and CO₂Not only cyclic propylene carbonate but also polycarbonate units of the formula (IXa) are produced

And on the other hand a polyether ester carbonate polyol containing a polyether unit represented by the formula (IXb).

Reaction mixture is passed through¹H-NMR spectroscopy.

The ratio of the amounts of cyclic propylene carbonate to polyetherestercarbonate polyol (selectivity; g/e ratio) and the proportion of unconverted monomers (propylene oxide R)_POLactide R_LactideIn mole%) by¹H-NMR spectroscopy. For this purpose, samples of the reaction mixture obtained after the reaction were in each case dissolved in deuterated chloroform and the spectra were recorded on the Bruker companyMeasured on a meter (AV400, 400 MHz).

Subsequently, the reaction mixture was diluted with dichloromethane (20 ml) and the solution was passed through a falling film evaporator. The solution (0.1 kg in 3 h) flowed down the inner wall of a tube of diameter 70 mm and length 200 mm, which had been heated from the outside to 120 ℃, wherein the reaction mixture was uniformly distributed as a thin film on the inner wall of the falling-film evaporator, respectively, by three rollers rotating at 250rpm and having a diameter of 10 mm. Inside the tube, a pump was used to set a pressure of 3 mbar. The reaction mixture purified to remove volatile components (unconverted epoxide, cyclic carbonate, solvent) was collected in a receiver at the lower end of a heated tube.

By passing¹H-NMR spectroscopy measures the molar ratio of carbonate groups to ether groups (e/f ratio) in the polyether ester carbonate polyol and the molar proportion of lactide incorporated into the polymer. For this purpose, samples of the purified reaction mixture were in each case dissolved in deuterated chloroform and measured on a spectrometer (AV400, 400MHz) from Bruker.

For integration¹The relevant resonances in the H-NMR spectrum (based on TMS = 0 ppm) are as follows:

i1: 1.10-1.17 ppm CH of polyether units₃The resonance region corresponds to three hydrogen atoms,

i2: 1.25-1.34 ppm CH of polycarbonate units₃The resonance region corresponds to three hydrogen atoms,

i3: 4.48-4.58 ppm CH of cyclic carbonate, the resonance region corresponding to one hydrogen atom,

i4: 2.95-3.00 ppm of the free, unreacted CH group of propylene oxide, the resonance region corresponding to a hydrogen atom.

I5: 1.36-1.54 ppm CH of polylactide units₃The resonance region corresponds to six hydrogen atoms,

i6: 1.59-1.62 ppm CH of free, unreacted lactide₃The resonance region corresponds to six hydrogen atoms,

i7: 6.22-6.29 ppm CH groups of the double bonds obtained by incorporating maleic anhydride into the polymer, the resonance regions corresponding to two hydrogen atoms,

i8: 7.05 ppm CH groups of free, unreacted maleic anhydride, the resonance region corresponding to two hydrogen atoms.

Shown are the molar ratio of the amount of carbonate units in the cyclic propylene carbonate to the polyether ester carbonate polyol (selectivity g/e), and the molar ratio of carbonate groups to ether groups in the polyether ester carbonate polyol (e/f), and the proportion of unconverted propylene oxide (in mol%) and lactide (in mol%).

These values are calculated as follows for the following cases, taking into account the relative intensities:

polyether ester carbonate polyol a: polyol obtained by trimerization of propylene oxide, carbon dioxide and lactide

Polyether ester carbonate polyol B: polyol obtained by trimerization of propylene oxide, carbon dioxide and maleic anhydride

Molar ratio of the amount of carbonate units in the cyclic propylene carbonate to the polyether ester carbonate polyol (selectivity g/e):

molar ratio of carbonate groups to ether groups (e/f) in polyether ester carbonate polyol:

CO incorporation into polyetherestercarbonate polyols A₂The ratio (in weight percent) of:

the proportion (in% by weight) of lactide incorporated in the polyetherestercarbonate polyol a:

based on activationAnd the molar proportion of unconverted propylene oxide (UR in mol%) based on the sum of the amounts of propylene oxide used in the copolymerization_PO) Calculated by the following formula:

molar proportion of unconverted lactide (UR in mol%) based on the sum of the amounts of lactide used in activation and copolymerization_Lactide) Calculated by the following formula:

CO incorporation into polyetherestercarbonate polyols B₂The ratio (in weight percent) of:

the proportion (in wt.%) of MSA incorporated in the polyetherestercarbonate polyol B:

OH number (hydroxyl number) was determined in accordance with DIN 53240-2 (11 months 2007).

Number average molecular weight M of the resulting polyether ester carbonate polyol_nAnd a weight average molecular weight M_wAs determined by Gel Permeation Chromatography (GPC). According to DIN 55672-1 (8 months 2007): "gel permeation chromatography, part 1-tetrahydrofuran as eluent" (SECURITY GPC System from PSS Polymer Service, flow rate 1.0 ml/min; column: 2 XPSS SDV Linear M, 8X 300 mm, 5 μ M; RID detector). Here, polystyrene samples of known molar mass are used for calibration. Polydispersity as M_w/M_nAnd (4) calculating the ratio.

Example 1: by propylene oxide, 20% by weight lactide and CO₂Of a mixture of (A) trimerized poly(s) having a functionality of 2.0Ether ester carbonate polyols

Step (alpha)

A300 ml pressure reactor equipped with a gas introduction stirrer was first loaded with a mixture of DMC catalyst (18 mg) and PET-I (30 g) and stirred at 130 ℃ for 30 minutes under a partial vacuum (50 mbar) with argon passing through the reaction mixture (800 rpm).

Step (beta)

15 bar of CO are pressed in₂(wherein a slight drop in temperature was observed) and the temperature of 130 ℃ had been reached again, 3.0 g of the monomer mixture (20% by weight of lactide dissolved in propylene oxide) were metered in by means of an HPLC pump (1 ml/min). The reaction mixture was stirred (800 rpm) at 130 ℃ for 20 minutes. The second and third repeated additions of 3.0 g of monomer mixture.

Step (gamma)

The temperature was readjusted to 105 ℃ and during the subsequent step further CO was metered in using a mass flow regulator₂The pressure in the pressure reactor was maintained at 15 bar. With stirring, a further 51.0 g of monomer mixture (20% by weight of lactide dissolved in propylene oxide) was metered in by means of an HPLC pump (1 mL/min), with stirring of the reaction mixture being continued (800 rpm). After the addition of the monomer mixture (20% by weight lactide dissolved in propylene oxide) was stopped, the reaction mixture was stirred for an additional 30 minutes at 105 ℃. The reaction was terminated by cooling the pressure reactor in an ice bath, releasing the overpressure and analyzing the resulting product. The properties of the obtained polyether ester carbonate polyol are shown in table 1.

Example 2: by propylene oxide, 20% by weight maleic anhydride and CO₂Of a mixture of (A) a polyetherestercarbonate polyol having a functionality of 2.0

Step (alpha)

Step (ii) of(β)

15 bar of CO are pressed in₂(wherein a slight drop in temperature was observed) and the temperature of 130 ℃ had been reached again, 3.0 g of the monomer mixture (20% by weight of maleic anhydride dissolved in propylene oxide) were metered in by means of an HPLC pump (1 ml/min). The reaction mixture was stirred (800 rpm) at 130 ℃ for 20 minutes. The second and third repeated additions of 3.0 g of monomer mixture.

Step (ii) of(γ)

The temperature was readjusted to 105 ℃ and during the subsequent step further CO was metered in using a mass flow regulator₂The pressure in the pressure reactor was maintained at 15 bar. A further 51.0 g of monomer mixture (20% by weight of maleic anhydride dissolved in propylene oxide) are metered in by means of an HPLC pump (1 mL/min) with stirring, the reaction mixture being stirred further (800 rpm). After the addition of the monomer mixture (20% by weight maleic anhydride dissolved in propylene oxide) had ceased, the reaction mixture was stirred for a further 30 minutes at 105 ℃. The reaction was terminated by cooling the pressure reactor in an ice bath, releasing the overpressure and analyzing the resulting product. The properties of the obtained polyether ester carbonate polyol are shown in table 1.

Table 1: comparison of the results of examples 1 and 2

Examples	1	2*
			Selectivity g/e	0.05	0.03
Monomer mixture	20% by weight of lactideIn PO	20 wt% MSA in PO
			CO₂Incorporation [ by weight ]]	11.2	13.1
M_n [g/mol]	4223	4173
			PDI	1.1	1.1
OH number [ mg KOH/g]	36.5	34.6
			Viscosity [ mPas]	3917	12325

Comparative example.

The viscosity of the polyether ester carbonate polyol prepared by the addition of lactide (example 1) is lower than the polyether ester carbonate polyol without the addition of lactide (example 2).

Claims

1. A process for preparing polyether ester carbonate polyols by the catalytic addition of alkylene oxides and carbon dioxide onto H-functional starter substances in the presence of double metal cyanide catalysts, comprising the following steps:

characterized in that lactide is metered into the reactor in step (. gamma.).

2. The process according to claim 1, characterized in that step (α) is carried out in the absence of lactide.

3. The process according to claim 1 or 2, characterized in that lactide is used in an amount of 5 to 40% by weight, based on the total amount of alkylene oxide used.

4. The process according to claim 1 or 2, characterized in that lactide is used in an amount of 10 to 30% by weight, based on the total amount of alkylene oxide used.

5. The process according to any one of claims 1 to 4, characterized in that after step (α)

(β) adding a partial amount of alkylene oxide to the mixture from step (α) at a temperature of from 90 to 150 ℃ and subsequently interrupting the addition of alkylene oxide compound and/or lactide, wherein step (β) is carried out in particular under an inert gas atmosphere, under an inert gas-carbon dioxide mixture atmosphere or under a carbon dioxide atmosphere.

6. Process according to any of claims 1 to 5, characterized in that in step (γ) the H-functional starter substance, alkylene oxide and lactide are metered continuously into the reactor in the presence of carbon dioxide.

7. Process according to any of claims 1 to 6, characterized in that the metering of the H-functional starter substance is terminated at a point in time before the addition of alkylene oxide and/or lactide in step (γ).

8. The process as claimed in any of claims 1 to 7, characterized in that in step (γ) H-functional starter substance, alkylene oxide, lactide and double metal cyanide catalyst are metered continuously into the reactor and the resulting reaction mixture is removed continuously from the reactor.

9. The process of claim 8 wherein the double metal cyanide catalyst is continuously added in suspension in the H-functional starter material.

10. The process as claimed in claim 8 or 9, characterized in that in step (δ) downstream of step (γ), the reaction mixture continuously removed in step (γ) with an alkylene oxide content of from 0.05 to 10% by weight is transferred to a postreactor and a postreaction is carried out therein, in order to reduce the free alkylene oxide content of the reaction mixture to less than 0.05% by weight.

11. A process according to any one of claims 1 to 10, characterised in that the lactide used is at least one compound of formula (II),

12. The process according to any one of claims 1 to 10, characterized in that the lactide is selected from the group consisting of 1, 4-dioxane-2, 5-dione, (S, S) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, (R, R) -3, 6-dimethyl-1, 4-dioxane-2, 5-dione, meso-3, 6-dimethyl-1, 4-dioxane-2, 5-dione and 3-methyl-1, 4-dioxane-2, 5-dione, 3-hexyl-6-methyl-1, 4-dioxane-2, 5-dione, 3, 6-bis (but-3-en-1-yl) -1, 4-dioxane-2, 5-dione (in each case including the optically active form).

13. The process according to any one of claims 1 to 12, characterized in that the H-functional initiator substance is selected from the group consisting of alcohols, amines, thiols, aminoalcohols, thiol-containing, hydroxyl esters, polyether polyols, polyester ether polyols, polycarbonate polyols, polyether carbonate polyols, polyethyleneimines, polyether amines, polytetrahydrofuran, polyether thiols, polyacrylate polyols, castor oil, monoglycerides or diglycerides of ricinoleic acid, monoglycerides of fatty acids, chemically modified monoglycerides, diglycerides and/or triglycerides of fatty acids and C1-C24 alkyl esters of fatty acids containing an average of at least 2 OH groups per molecule.

14. The process according to any one of claims 1 to 12, characterized in that the H-functional starter substance is selected from the group consisting of ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 4-diol, pentane-1, 5-diol, 2-methylpropane-1, 3-diol, neopentyl glycol, hexane-1, 6-diol, octane-1, 8-diol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, di-and trifunctional polyether polyols or mixtures thereof, wherein the polyether polyol is formed from a di-or tri-H-functional starter substance and propylene oxide or a di-or tri-H-functional starter substance, propylene oxide and ethylene oxide and has in particular a molecular weight M of from 62 to 4500 g/mol._nAnd a functionality of 2 to 3.

15. Process according to any one of claims 1 to 14, characterized in that the suspension medium free of H functions is selected from the group consisting of 4-methyl-2-oxo-1, 3-dioxolane, 1, 3-dioxolane-2-one and mixtures of 4-methyl-2-oxo-1, 3-dioxolane and 1, 3-dioxolane-2-one.